patch wiki instructions fail

[bernstei]

I'm trying to follow the instructions in ​https://trac.macports.org/wiki/howto/PatchLocal to make a patch for grace (to fix the XmRegisterConverters issue). I can get through step 1, but the first item in step 2 "port patch grace-devel" doesn't work. It tries to download dist files for grace-devel-5.1.25.tar.gz from various mirrors, which obviously don't exist:

bernsteiadmin@vpn214062 ports % sudo port patch grace-devel
Portfile changed since last build; discarding previous state.
--->  Fetching distfiles for grace-devel
--->  Attempting to fetch grace-devel-5.1.25.tar.gz from https://ywg.ca.distfiles.macports.org/mirror/macports/distfiles/grace-devel
--->  Attempting to fetch grace-devel-5.1.25.tar.gz from http://ykf.ca.distfiles.macports.org/MacPorts/mpdistfiles/grace-devel

I'm not sure how it's supposed to work - am I supposed to be making a local copy of the distfile, and that step is missing? Or does it need to be told that the dist files to download are still called "grace", but after the local patch has been applied the port should be named "grace-devel", and that step is missing?